1. Field of the Invention
The present invention relates to apparatus for the automatic refuelling of vehicles.
2. Description of the Related Art
Swedish Patent Specification No. 8901674-5 describes an apparatus for the automatic refuelling of vehicles, primarily cars, which includes a robot having a robot head provided with a fuelling nozzle or like device, and which is constructed to move the fuelling nozzle automatically from a rest position to a vehicle fuelling position in response to sensing and control means, and after the vehicle has been placed in a predetermined position relative to the robot.
According to that patent specification, the refuelling nozzle includes a rigid, first tubular element, preferably a metal tube, which is intended to be connected by the robot to an adapter which is provided with a hole and which is attached to the upper orifice of the vehicle fuel-tank pipe. A flexible, second tube, preferably of a plastic tube material, is arranged within the first, rigid tube for movement between a first end position in which the outer, free end of the second tube is located within the first tube, to a second end position in which the second tube projects out from the first tube. A tube connection is provided between said hole and the vehicle fuel-tank pipe. The robot is constructed to move the free end of the first tube into abutment with, or to a position in the immediate vicinity of the adapter in a first movement step and to move the free end of the second tube out of the first tube and down into said tube connection or down into the fuel-tank pipe of the vehicle in a second movement step, and to pump fuel through the second tube and down into the fuel tank of the vehicle in a third step. When fuelling of the vehicle is completed, the robot repeats the two first-mentioned steps, but in the reverse order.
A positioning system as mentioned in the aforesaid patent application includes a transceiver unit mounted on the robot head, which transceiver unit operates at microwave frequency, and a passive transponder is placed on the vehicle in a predetermined position relative to the fuel-tank pipe.
Although the robot head is positioned very accurately in relation to the vehicle fuel-tank flap, or cover plate, and therewith in relation to the fuel-tank pipe, the load acting on the vehicle can change from the time at which the robot head is initially positioned to the time at which fuelling of the vehicle is commenced. This change in load may be caused by a person leaving the vehicle, for instance.
Furthermore, when positioning the robot head it is necessary to be able to accept within accepted tolerances deviations caused by measuring errors or by an incorrectly positioned transponder on the vehicle.
It is thus desirable to be able to permit certain deviations between the ideal position of the robot head and the fuel-tank pipe when docking between the first, outer tube and the fuel-tank pipe, and the actual position occupied by the robot head immediately prior to docking.
Another problem is that docking must be monitored both prior to and during a fuelling operation, so that fuelling can be carried out in a safe manner.
These desiderata are fulfilled by the present invention.